Sanitary evaporator assembly

ABSTRACT

An ice maker evaporator assembly having an evaporator pan with a back wall and left, right, top and bottom sidewalls extending from the back wall, and a freeze plate located within the evaporator pan. A serpentine tubing is thermally coupled to the back wall of the evaporator pan opposite the left, right, top and bottom sidewalls. A first layer of insulation is formed on the serpentine tubing. An evaporator housing having a housing back wall and housing left, right, top and bottom sidewalls extending from the housing back wall is attached to the evaporator pan and covers serpentine tubing. A second layer of insulation is formed on top of the first layer of insulation.

FIELD OF THE INVENTION

This invention relates generally to ice makers and, more particularly,to an evaporator assembly for an ice maker.

BACKGROUND OF THE INVENTION

Ice making machines, or ice makers, typically comprise a refrigerationand ice making system that employs a source of refrigerant flowingserially through a compressor, a heat rejecting heat exchanger (e.g., acondenser), a refrigerant expansion device, and an evaporator assemblyincluding a freeze plate comprising a lattice-type cube mold.Additionally, typical ice makers employ gravity water flow and iceharvest systems that are well known and in extensive use. Ice makershaving such a refrigeration and ice making system are often disposed ontop of ice storage bins, where ice that has been harvested is storeduntil it is needed. Such ice makers may also be of the “self-contained”type wherein the ice maker and ice storage bin are contained in a singleunit. Such ice makers have received wide acceptance and are particularlydesirable for commercial installations such as restaurants, bars, hotelsand various beverage retailers having a high and continuous demand forfresh ice.

In these ice makers, water is supplied at the top of an evaporatorassembly which directs the water in a tortuous path toward a water pump.A portion of the supplied water collects on the freeze plate, freezesinto ice and is identified as sufficiently frozen by suitable meanswhereupon the freeze plate is defrosted such that the ice is slightlymelted and discharged therefrom into an ice storage bin. Typically,these ice machines can be classified according to the type of ice theymake. One such type is a grid style ice maker which makes generallysquare ice cubes that form within individual grids of the freeze platewhich then form into a continuous sheet of ice cubes as the thickness ofthe ice increases beyond that of the freeze plate. After harvesting, thesheet of ice cubes will break into individual cubes as they fall intothe ice storage bin. Another type of ice maker is an individual ice cubemaker which makes generally square ice cubes that form within individualgrids of the freeze plate which do not form into a continuous sheet ofice cubes. Therefore, upon harvest individual ice cubes fall from thefreeze plate and into the ice storage bin. Control means are provided tocontrol the operation of the ice maker to ensure a constant supply ofice. Various embodiments of the invention can be adapted to either typeof ice maker, and to others not identified, without departing from thescope of the invention.

Typical ice makers have extraneous heat transfer on the back surfaces ofthe evaporator assembly in which energy or heat is removed from the airinside the ice maker rather than from the water to be frozen into ice.This extraneous heat transfer represents inefficiency in typical icemakers. Additionally, evaporator assemblies in typical ice makers willcondense and freeze moisture in the air inside the ice maker and/or willcreate frost on the back of the evaporator assembly where there isexposed copper. This presents another route for extraneous heat transferas energy is transferred to condense and freeze airborne water or tocreate frost rather than cooling the water to be frozen into ice. Then,when warm refrigerant is directed through the serpentine tube of typicalevaporators to harvest ice from the evaporator, a portion of the energythat is intended for melting the ice will instead be absorbed by thefrost on the back side of the evaporator. Again, this extraneous heattransfer reduces the efficiency of typical ice makers.

Certain ice makers, particularly those of the flaked, pellet, and nuggetcontinuous-extrude type ice makers may include foam insulationsurrounding the refrigerant tubing. However, one cannot simply use blowninsulation by itself, because polyurethane is only 90% closed cell. Theremaining 10% may fill with moisture overtime and ultimately break downthe entire foam. The soggy foam (now frozen) would potentially renderthe ice maker un-harvestable, leading to catastrophic failure.

Another issue with typical ice makers is that any water that contactsand/or resides on the back side of the evaporator (e.g., from waterleaks, condensation, and/or frost formation) creates a potential fordamage to the evaporator from the expansion and contraction associatedwith the freezing and thawing of such water. The presence of thismoisture also increases the possibility for corrosion of the evaporator.

Furthermore, the air inside a typical ice maker can be contaminated withairborne contaminants from the ambient environment (e.g., restaurant,hospital, bar, etc.). In typical ice makers, the back side of theevaporator is exposed to these contaminants and the backside of theevaporator typically does not get cleaned due to a lack of access and alack of instruction on how to clean the back side of the evaporator.Accordingly, there can be a buildup of biological contaminants on theback side of typical evaporators. When the backside of the evaporatorthen condenses moisture and drips into the ice maker, the sump below theevaporator, and/or the ice storage bin below the ice maker, thatdripping condensation may contain biological contaminants and thus maycontaminate the ice making water and/or the produced ice. As a result ofthis and because the back side of the evaporator is considered in thefood zone of typical ice makers, the back side of the evaporator shouldbe cleaned periodically. This cleaning step can be a difficult,expensive, and/or undesirable step. Consequently, the cleaning of theback side of the evaporators of typical ice makers is rarely, if ever,done.

SUMMARY OF THE INVENTION

One aspect of the invention is directed to an evaporator assembly for anice maker, the evaporator assembly having an evaporator, an evaporatorpan, and an evaporator housing. The evaporator has a front side and aback side and includes a rectangular evaporator pan comprising a backwall and left, right, top and bottom sidewalls extending from the backwall. Attached to the back side of the evaporator pan is a serpentinetube through which cold refrigerant flows to lower the temperature ofthe evaporator so that ice can be formed therein. A first layer ofinsulation is formed on the serpentine tubing. An evaporator housinghaving a housing back wall and housing left, right, top and bottomsidewalls extending from the housing back wall is attached to theevaporator pan and covers serpentine tubing. A second layer ofinsulation is formed on top of the first layer of insulation, forexample, by pouring a flexible, liquid coating on the tubing andallowing the coating to cure and substantially cover the tubing. Theevaporator assembly further includes an evaporator housing comprising ahousing back wall and housing left, right, top and bottom sidewallsextending from the housing back wall, such that the housing covers andtubing and forms a cavity therein. The cavity may be filed with a secondinsulating material.

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects and advantages of the invention willbecome more fully apparent from the following detailed description,appended claims, and accompanying drawings, wherein the drawingsillustrate features in accordance with exemplary embodiments of theinvention, and wherein:

FIG. 1 is a right perspective view of an evaporator assembly accordingto one embodiment of the invention;

FIG. 2 is an exploded right perspective view of an evaporator assemblyaccording to one embodiment of the invention;

FIG. 3 is a front view of an evaporator pan according to one embodimentof the invention;

FIG. 4 is a back view of an evaporator according to one embodiment ofthe invention;

FIG. 5 is a right view of an evaporator according to one embodiment ofthe invention;

FIG. 6 is a rear view of an evaporator housing according to oneembodiment of the invention;

FIG. 7 illustrates a refrigerant tubing covered by a first pourableinsulation in accordance with one embodiment of the invention;

FIG. 8 is a rear perspective view of an evaporator assembly according toan embodiment of the invention;

FIG. 9 is a perspective view of a back wall of an evaporator housingaccording to an embodiment of the invention;

FIG. 10 is an exploded perspective view of a back wall of an evaporatorhousing according to an embodiment of the invention;

FIG. 11 is an exploded perspective view of an evaporator housingaccording to an embodiment of the invention;

FIG. 12 is an exploded perspective view of portions of an evaporatorhousing according to an embodiment of the invention; and

FIG. 13 is a perspective view of the back side of the evaporator housingaccording to an embodiment of the invention.

Like reference numerals indicate corresponding parts throughout theseveral views of the drawings.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. All numbers expressing measurements and soforth used in the specification and claims are to be understood as beingmodified in all instances by the term “about.” It should also be notedthat any references herein to front and back, right and left, top andbottom and upper and lower are intended for convenience of description,not to limit an invention disclosed herein or its components to any onepositional or spatial orientation.

As described herein, embodiments of the invention are directed to anevaporator assembly wherein the back side of the evaporator is covered,insulated, exempt from NSF regulations, and protected from heat loss andthe damaging effect of the water and corrosion. Because the back side ofthe evaporator is covered, it does not need to be plated (withelectroless nickel, for example), saving considerable cost and it cannotcontaminate the ice making water.

With reference to FIGS. 1-6, an embodiment of evaporator assembly 100 isdescribed. Evaporator assembly 100 includes evaporator 110 and anevaporator housing formed by housing top 140, bottom 150, sides 160 and170, and back 180. Preferably, the top 140, bottom 150, sides 160 and170, and back 180 of the evaporator housing are plastic. The top 140,bottom 150, sides 160 and 170, and back 180 of the evaporator housingmay have features allowing them to be assembled together in a variety ofways, including snap-fit features, bolts and nuts, etc. The innersurfaces of the top 140, bottom 150, sides 160 and 170 may include agasket material to aid in sealing the evaporator housing water tight.Evaporator 110 includes an evaporator pan 120 having a back wall 300 anda left sidewall 310, a right sidewall 320, a top sidewall 330, and abottom sidewall 340 extending from back wall 300 toward the front sideof evaporator 110. Left, right, and top sidewalls 310, 330, 320, aresubstantially perpendicular to back wall 300 while bottom sidewall 340preferably angles slightly downward. The evaporator pan 120 includes aseries of studs 130 that may be used to mount evaporator assembly 100 toan internal structure of the ice maker (not shown). The evaporatorhousing may have corresponding mating openings 190, through which thestuds 130 may pass.

A population of vertical and horizontal strips 240, 250 are secured inevaporator pan 120 to form a lattice of ice cube “molds.” Evaporator pan120 with vertical and horizontal strips 240, 250 may also be called afreeze plate. Attached to the back side of back wall 300 of evaporatorpan 120 is a serpentine tube 200 through which cold refrigerant flows tolower the temperature of evaporator 110 so that ice can be formedtherein. Serpentine tube 200 includes inlet tube 220 and outlet tube 210which extend through evaporator assembly 100, as described more fullyelsewhere herein. Locating the inlet tube 220 at the bottom of theevaporator assembly 100 assists in ensuring an even distribution oftemperature across the evaporator. The serpentine tube 200 may beattached to the back side of back wall 300 of the evaporator pan 120 ina number of conventional ways, including using a soldering or brazingprocess.

The components of evaporator 110 are preferably formed of copper. Tosatisfy the water contact cleanliness requirements of NSF for commercialice machines, all areas of evaporator 110 that are considered to be inthe “food zone” of the ice maker cannot be bare copper and thus must beplated. Any portion of evaporator 110 that could potentially drip waterinto the food zone is considered to be inside the food zone and mustcomply with this requirement. Because of this requirement, typical icemachine evaporators must be completely plated such that no un-plated,bare copper surfaces are exposed. Typical evaporators are exposed on allsides, thus the entire surface of typical evaporators—front andback—must be plated. This plating, typically a thin layer of electrolessnickel (EN), is quite expensive, costing roughly as much as the rest ofthe evaporator. As described more fully elsewhere herein, because theback side of evaporator 110 is covered by evaporator housing, the backside of evaporator 110 does not need to be plated. Thus only the frontside of back wall 300, sidewalls 310, 320, 330, and 340 of evaporatorpan 120 are plated. The back side of back wall 300 and serpentine tubing200 are not required to be plated.

Referring now to FIG. 6, two passageways 610, 620 extend through backwall 180 of evaporator housing. Passageways 610, 620 permit inlet andoutlet tubes 220, 210, respectively, of serpentine tube 200 to passthrough back wall 300 of the evaporator housing such that serpentinetube 200 can be coupled with the remaining components of therefrigeration system of an ice maker (not shown). Passageways 610, 620are preferably circular in shape; however, passageways may berectangular, square, ovular, etc. without departing from the scope ofthe invention. Rubber grommets (not shown) may be inserted intopassageways 610, 620 to seal any gap between passageways 610, 620 andinlet and outlet tubes 220, 210, respectively, of serpentine tube 200.In certain embodiments, a caulk or sealant may be used in addition to orin place of grommets to seal any gap between passageways 610, 620 andinlet and outlet tubes 220, 210.

A third passageway 630 may be provided in the back wall 180 in order toinject insulating material into the interior of the evaporator housingassembly 100 as described below.

As illustrated in FIG. 7, the evaporator assembly 100 further includesan insulating material 710 layered over at least a majority of thelength of the serpentine tube 200. The insulating material 710 minimizesthe amount of heat dissipated by the serpentine tube 200 and provides awater-tight seal. Preferably, the insulating material 710 is aheavy-bodied, water-based, vinyl acrylic, general-purpose mastic that istypically used in both interior and exterior insulation systems.Examples of insulating material 710 include two-part silicone materialssuch as QSil 550 from Quantum Silicones LLC of Richmond, Va.

Preferably, the insulating material 710 is applied in liquid form ontothe serpentine tubing 200 to a thickness of approximately about 5 mm toabout 12 mm. The insulating material 710 then cures, forming an integrallayer of insulation that is impervious to water. In addition, theintegral layer of insulation has no joints through which water can leak,will not rust, and adds rigidity and strength. As the insulatingmaterial 710 is poured in a liquid form, it cures into a mold thatmatches the geometry of the serpentine tubing 340 and can fill in allgaps within the back side of the evaporator pan.

After attaching the serpentine tube 200 to the evaporator pan 120, andadding the insulating material 710 surrounding the serpentine tube 200,the evaporator assembly 100 may be assembled. Thus the five componentsof the evaporator housing, namely housing top 140, bottom 150, sides 160and 170, and back 180 may be assembled together surrounding theevaporator pan 110 in order to form the complete assembly 100. Formingthe assembly results in a cavity formed between the back side ofevaporator 110 (holding the serpentine tube 200) and the front side ofback wall 180 of evaporator housing, and further enclosed by the housingtop 140, bottom 150 and sides 160 and 170.

As illustrated in FIGS. 8-13, in certain embodiments, the back 180 mayinclude one or more raised edges 182, 184, 186, and 188. As shown inFIGS. 9 and 10, the raised edges 182, 184, 186, and 188 preferablysurround the perimeter of the back 180. The raised edges 182, 184, 186,and 188 extend outwardly away from the inner surface of the back 180(i.e., the surface facing the serpentine tube 200). As shown in FIGS. 11and 12, the raised edges 182, 184, 186, and 188 initially rest withingrooves 172, 174, 176, and 178 formed in the top 140, bottom 150, andsides 160 and 170.

The back 180 may then be ultrasonically welded to the top 140, bottom150, and sides 160 and 170 in order to seal the entire assembly togetheras shown in FIG. 13. The raised edges 182, 184, 186, and 188, which maybe a raised triangular bead of material molded onto the surface of theback 180, concentrate the ultrasonic energy to rapidly initiate thesoftening and melting of the surface of the back 180 and grooves 172,174, 176, and 178 as is known to those skilled in the art of ultrasonicwelding. During welding, the raised edges 182, 184, 186, and 188 meltflat to seal the back 180 into the grooves 172, 174, 176, and 178.

In various embodiments, the cavity may be filled with foam afterevaporator assembly 100 is assembled. The foam may be open- orclosed-cell foam comprised, for example, of polystyrene or polyurethane,etc. Preferably, the foam is an expanding-type foam that can be sprayedinto the cavity through passage 630. The foam preferably conforms to theback side of evaporator 110 so that it covers all or substantially allof the back side of evaporator pan 120 and the insulated serpentine tube200 and fills all or substantially all of cavity. The foam may besprayed into cavity after evaporator 110 and evaporator housing areassembled together. Another acceptable form is a two-part liquid formsold under the brand name Ecomate, in which the two parts mix and curein place. After cavity is filled with sufficient amount of foam, a plug(not shown) may be inserted into or over the passageway 630 and may beheld and sealed in place by the foam inside cavity. Additionally oralternatively, the plug may be held in by any type of sealant and/oradhesive, including, but not limited to, silicone caulk.

Filling the cavity provides insulation to the back side of evaporator110 thus reducing or eliminating extraneous heat transfer on the backside of evaporator 110 which is common with typical evaporators asdescribed more fully elsewhere herein. Consequently, filing the cavitywith foam reduces or eliminates the possibility for condensation orfrost to form on the back side of evaporator 110, reduces or eliminatesthe possibility of the back side of evaporator 110 corroding, andincreases the efficiency of both forming and harvesting ice cubes fromevaporator pan 120 because extraneous heat on the back side ofevaporator 110 is essentially eliminated. Furthermore, the foam withinthe cavity is completely protected from any moisture condensing on theserpentine tubing 200 by the insulating material 710. As an alternativeto filling the cavity with foam, the insulating material 710 may beapplied to a thicker layer. Alternatively, one may use a single layer ofstandard blown foam in place of the insulating material 710,particularly if a closed cell blown foam (about 99.5% closed) becomescommercially available.

The increase in insulation effectively allows one to reduce the size ofthe evaporator 110, thus minimizing the size of the required compressorand condenser for the identical ice making capacity. In tests of theembodiment described here, an icemaker can achieve slightly largeramounts of produced ice using significantly less energy.

Thus, there has been shown and described a novel evaporator assembly foran ice maker, particularly useful with batch-type ice makers. It will beapparent, however, to those familiar in the art, that many changes,variations, modifications, and other uses and applications for thesubject devices and methods are possible. All such changes, variations,modifications, and other uses and applications that do not depart fromthe spirit and scope of the invention are deemed to be covered by theinvention which is limited only by the claims which follow.

What is claimed is:
 1. An evaporator assembly for an ice makercomprising: an evaporator pan comprising a back wall and left, right,top and bottom sidewalls extending from the back wall; a freeze platelocated within the evaporator pan; a serpentine tubing thermally coupledto the back wall of the evaporator pan opposite the left, right, top andbottom sidewalls; a first layer of insulation formed on the serpentinetubing; a second layer of insulation formed on top of the first layer ofinsulation; and an evaporator housing comprising a housing back wall andhousing left, right, top and bottom sidewalls extending from the housingback wall, wherein the evaporator housing is attached to the evaporatorpan and covers serpentine tubing, and the first and second layers ofinsulation.
 2. The evaporator assembly of claim 1, wherein theevaporator pan and evaporator housing form a cavity and wherein thecavity is filled with the second layer of insulation.
 3. The evaporatorassembly of claim 1, wherein the first layer of insulation comprises aliquid form of insulation that cures into a mold that substantiallymatches a geometry of the serpentine tubing.
 4. The evaporator assemblyof claim 3, wherein the first layer of insulation is poured over theserpentine tubing in liquid form and cures into a solid form.
 5. Theevaporator assembly of claim 1, wherein the first layer of insulationcomprises a sprayed mastic insulation.
 6. The evaporator assembly ofclaim 1, wherein the first layer of insulation comprises a taped masticinsulation.
 7. The evaporator assembly of claim 1, wherein the back sideof the evaporator pan is unplated.
 8. The evaporator assembly of claim1, wherein the housing back wall is attached to the housing left, right,top and bottom sidewalls via an ultrasonic welding process.
 9. Theevaporator assembly of claim 8, wherein the housing back wall comprisesa raised edge that melts during the ultrasonic welding process to sealthe housing back wall to the housing left, right, top and bottomsidewalls.
 10. An evaporator assembly for an ice maker comprising: anevaporator pan comprising a back wall and left, right, top and bottomsidewalls extending from the back wall; a freeze plate located withinthe evaporator pan; a serpentine tubing thermally coupled to the backwall of the evaporator pan opposite the left, right, top and bottomsidewalls; a first layer of insulation formed on the serpentine tubing;an evaporator housing formed attached to the evaporator pan and coveringthe serpentine tubing and the first layer of insulation, the evaporatorhousing formed using an ultrasonic process and comprising: housing left,right, top and bottom sidewalls, wherein each sidewall comprises agroove; and a housing back wall seated into the grooves of thesidewalls, the housing back wall comprising a raised edge that meltsduring the ultrasonic welding process to seal the housing back wall tothe housing left, right, top and bottom sidewalls.
 11. The evaporatorassembly of claim 10 wherein the evaporator pan and evaporator housingform a cavity and wherein the cavity is filled with a second layer ofinsulation formed on top of the first layer of insulation.
 12. A methodfor forming an evaporator assembly for an ice maker comprising the stepsof: forming an evaporator pan comprising a back wall, and left, right,top and bottom sidewalls extending from the back wall; forming andlocating a freeze plate within the evaporator pan; attaching aserpentine tubing for thermally cooling the evaporator pan to the backwall of the evaporator pan such that serpentine tubing is thermallycoupled to the back wall of the evaporator pan opposite the left, right,top and bottom sidewalls; pouring a first layer of insulation in aliquid form on the serpentine tubing in order to substantially cover theserpentine tubing; forming an evaporator housing comprising a back walland housing left, right, top and bottom sidewalls extending from thehousing back wall; waiting until the first layer of insulationsubstantially cures into a solid form; attaching the evaporator housingto the evaporator pan, wherein the housing back wall and housing left,right, top and bottom sidewalls form a cavity surrounding the serpentinetubing; and adding a second layer of insulation within the cavity of theevaporator housing.
 13. The method of claim 12 wherein the first layerof insulation comprises a liquid form of insulation that cures into amold that substantially matches a geometry of the serpentine tubing. 14.The method of claim 12 wherein the evaporator housing further comprisesone or more holes through which the second layer of insulation may beadded to the cavity of the evaporator housing.
 15. The method of claim12 wherein the second layer of insulation is added by blowing apolyurethane mixture through the one or more holes of the evaporatorhousing.
 16. The method of claim 12 wherein the back side of theevaporator pan is unplated.
 17. The method of claim 12 furthercomprising the step of ultrasonically welding the housing back wall tothe housing left, right, top and bottom sidewalls.
 18. The method ofclaim 17, wherein the housing back wall comprises a raised edge thatmelts during the ultrasonic welding process to seal the housing backwall to the housing left, right, top and bottom sidewalls.
 19. Anevaporator assembly for an ice maker comprising: an evaporator pancomprising a back wall and left, right, top and bottom sidewallsextending from the back wall; a freeze plate located within theevaporator pan; a serpentine tubing thermally coupled to the back wallof the evaporator pan opposite the left, right, top and bottomsidewalls; a first layer of insulation formed on the serpentine tubing;and an evaporator housing comprising a housing back wall and housingleft, right, top and bottom sidewalls extending from the housing backwall, wherein the evaporator housing is attached to the evaporator panand covers serpentine tubing, and the first and second layers ofinsulation.